This Phase I, II study is to define the local and systemic toxicity and immunomodulatory effects associated with peritumoral injections of fibroblasts genetically engineered to secrete IL-12 and evaluate the clinical efficacy of this procedure. A total of 18 patients with cutaneous cancer lesions of 4 types of cancer (melanoma, breast cancer, head & neck cancer and cutaneous T-cell lymphoma) will be enrolled in the preliminary study of this maximum tolerable or "possible" dosage study.